Contents

1. Contents 1.1 Main stages 1.2 Key issues specific to decommissioning 1.3 Main areas and activities 1.4 Differences between decommissioning and operation Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

2. Training objectives Upon completion of training trainees should be able to: • Explain the main tasks of decommissioning. • Determine the main decommissioning areas and activities. Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

3. 1.1 Main stages Decommissioning The term decommissioning refers to administrative and technical actions taken to allow removal of some or all of the regulatory controls from а nuclear facility (except for а repository, which is, by definition, subject to closure and not decommissioning). (IАЕА, “Decommissioning of nuclear power plants and research reactors”, Safety Standard Series WS-G-2.1, Vienna, 1999) Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

4. Decommissioning process All main activities in the decommissioning process are of significant direct or indirect importance to safety. They are connected to: • the immediate impacts on personnel safety; • shock on effects on safety during implementation of next step operations, including those that a re envisaged to take place after a considerable period of time elapses; • impact on inhabitants and the environment; • impact on future generations. Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

5. Decommissioning strategies • Immediate dismantling • Deferred dismantling (safe storage, safe enclosure) • Entombment Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

6. Construction2 years Science and Support35 years Authorisation Cleaning6 years Clearance Dismantling4 years An example of decommissioning strategy –« Passage »Project, Grenoble, France The main targets of « Passage » Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

7. Decontamination & Dismantling Phase Final Phase Preparation Phase Surveillance & Maintenance Phase Decontamination& Dismantling Phase Preparatory Phase Main stages of decommissioning Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

8. Preparatory phase • specification of the decommissioning plan • defueling and removal of the radioactive materials generated during operation; • evaluation of the quantity of which are to be generated at the dismantling; • preparation for and obtaining of licenses/permits; • actualization of the technical documentation of the nuclear facility; • including changes to the QА system; • development of training programs and training the instructors for maintaining qualification (requalification) of the personnel Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

9. Surveillance and maintenance phase • control over the normal operation and the condition of the systems; • environment monitoring; • classification the equipment; • partial removal of the equipment; • treatment and conditioning of the RАW; • actualisation of the decommissioning plan; • preparation for D&D stage activities; • development and implementation of training. Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

10. Dismantling and decommissioning phase • licensing of activities, related to dismantling; • installation of decontamination and dismantling equipment; • decontamination and dismantling; • qualification of equipment and materials; • treatment, conditioning, transportation and storage of RAW; • on-site and environmental monitoring; • site release (transition to the final phase – surveillance and release from regulatory control.) Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

11. KNPP units 1,2 decommissioning: Main concept • Post operation and preparation period • Safe enclosure (35 years) • Deferred dismantling (PHАRЕ Project BUL 9608-01-01 L001, Bеlgаtom– ЕWN, 2000) Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

12. 1.2 Key issues specific to decommissioning • Responsibilities • Regulatory framework • Safety • Planning • Considerations for radiation protection and environmental protection • Wastes Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

13. Key issues: Responsibilities States shall include provisions in their national legal framework for: • decommissioning, including the preparation of decommissioning strategies and plans; • establishment of а regulatory body for controlling decommissioning activities; • establishment of funding mechanisms for decommissioning; • development of а system for the management of the material resulting from decommissioning. Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

14. Key issues: Responsibilities The operator shall be responsible for all aspects of safety and environmental protection during the decommissioning activities, i.e.: • adequate level of safety; • perform softy and environmental impact assessments; • prepare and implement appropriate safety procedure; • apply good engineering practice; • ensure that staff are properly trained, qualified and competent; • establish а quality management programme, and • keep and submit records and reports as required by the regulatory body. Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

15. Key issues: Regulatory framework The regulatory body shall establish safety and environmental criteria for the decommissioning, including: • conditions on the end points of decommissioning; • limits and conditions for the removal of controls for facilities containing radionuclides and criteria for the clearance of material during and following decommissioning; • criteria for determining when а nuclear facility, or part of а facility is permanently shutdown; • require baseline survey of the site, including radiological conditions, prior to construction to obtain information that can be used for comparison purposes with the end state after decommissioning Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

16. Key issues: Safety Ensure the protection of workers, the public and the environment by means of: • thorough safety assessment of the hazards, fuel, stored on as part of а defense in depth system; • maintenance of integrity of the spent -site in а fuel pool; • taking into account in the safety assessment the total contamination and activation of the instillation after removal the RАM; • considering the new additional hazards created by specific decommissioning activities (decontamination, dismantling and demolition, removal of equipment and systems …); • defining and implementing the protective measures for industrial safety, fire protection and emergency planning. Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

17. Key issues • Planning • The adequate and timely planning of decommissioning activities to a very large extent reduces the risk and radiological consequences, concerning decommissioning activities. • Considerations for radiation protection and environmental protection • It is necessary that the national radiological protection requirements should be in compliance with the International basic standards on safety. • Wastes • RAW generation should be as less as possible (application of adequate techniques for decontamination and dismantling, recycling and re-use of materials). These problems are considered at length in the “Decommissioning Management ” course. Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

18. 1.3 Main areas and activities The main activities with an impact on safety during decommissioning include: • Initial characterization of the nuclear instillation • Defueling • Containment maintenance and modification • Decontamination • Dismantling • RАW management (treatment, conditioning, storage) and transport • Final radiological characterization • Organization and administrative control Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

19. Main areas and activities • Initial characterization of the nuclear instillation • Defueling • Radiological characterization of all premises • Final clean-up of pool channels and plug storage Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

20. Main areas and activities • Containment maintenance and modification • Decontamination • Dismantling Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

21. Main areas and activities (cont.) • RАW management (treatment, conditioning, storage) and transport • Final radiological survey Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

22. 1.4 Differences between decommissioning and operation Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

23. Differences between decommissioning and operation (cont.) Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

24. Differences between decommissioning and operation (cont.) Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"

25. References 1. IАЕА, Decommissioning of nuclear power plants and research reactors, Safety Standard Series WS-G-2.1, Vienna, 1999 2. IАЕА, Decommissioning of Nuclear Facilities, DRАFT SАFЕTY RЕQUIRЕMЕNTS, DS333, Nov 2004 3. Transition from Operation to Decommissioning, IАЕА TRS No420 Project BG/04/B/F/PP-166005, Program "Leonardo da Vinci"